Stainless Steel Seamless Pressure Tube — EN 10216-5 Coil Tube
Wenzhou Jixing Metal Materials Co., Ltd. presents a premium-grade stainless steel seamless pressure tube manufactured in accordance with the European standard EN 10216-5 (Steel tubes for pressure purposes — Non-alloy and alloy steel tubes for pressure purposes — Part 5: Technical delivery conditions for non-alloy and alloy steel tubes for pressure purposes). This coil tube product is specifically engineered for demanding pressure-containing applications and is fully compliant with the European Pressure Equipment Directive (PED), ensuring seamless integration into regulated industrial systems across the European Economic Area (EEA) and globally.
1. Product Overview
The EN 10216-5 stainless steel seamless coil tube is a precision-engineered pressure tube designed for service under elevated temperatures and pressures. Manufactured using advanced seamless forming techniques, this product eliminates weld seams that could serve as stress concentration points or failure initiators, thereby delivering superior mechanical integrity and fatigue resistance.
Available in coil form (盘管 / Coil Tube), this product offers significant advantages in downstream processing, including reduced material waste during cutting, improved logistics efficiency, and enhanced flexibility for on-site fabrication. The coil configuration enables continuous feed into bending, forming, and welding operations, making it ideal for large-scale pipeline installations and heat exchanger manufacturing.
Key Differentiator: Full PED (Pressure Equipment Directive) compliance with TC1/TC2 test category classification ensures this product meets the rigorous safety and performance requirements mandated by European regulatory authorities for pressure equipment design, manufacture, and inspection.
2. Material & Properties
2.1 Applicable Material Grades
EN 10216-5 covers a range of non-alloy and alloy steel grades. For stainless steel seamless pressure applications, the following material designations are commonly specified:
- 1.4301 / X5CrNi18-10 (AISI 304) — General-purpose austenitic stainless steel with excellent corrosion resistance
- 1.4401 / X5CrNiMo17-12-2 (AISI 316) — Molybdenum-enhanced austenitic grade with superior pitting and crevice corrosion resistance
- 1.4541 / X6CrNiTi18-10 (AISI 321) — Titanium-stabilized austenitic grade suitable for elevated temperature service
- 1.4571 / X8CrNiNb18-10 (AISI 347) — Niobium-stabilized variant for high-temperature structural applications
- 1.4539 / X10CrNi18-12 (AISI 310) — High-temperature austenitic grade for extreme thermal environments
2.2 Mechanical Properties (Typical Values at 20°C)
| Property | Grade 1.4301 (304) | Grade 1.4401 (316) | Grade 1.4541 (321) |
|---|---|---|---|
| Tensile Strength (Rm) — MPa | 520 – 700 | 515 – 730 | 520 – 700 |
| Yield Strength (Rp0.2) — MPa | ≥ 205 | ≥ 205 | ≥ 205 |
| Elongation (A5) — % | ≥ 35 | ≥ 35 | ≥ 35 |
| Density — g/cm³ | 7.93 | 8.00 | 7.93 |
| Thermal Expansion (20–100°C) — 10⁻⁶/K | 16.0 – 17.3 | 15.8 – 17.5 | 16.0 – 17.3 |
| Operating Temperature Range — °C | −196 to +870 | −196 to +870 | −196 to +900 |
2.3 Chemical Composition Requirements (Mass %)
| Element | 1.4301 (304) | 1.4401 (316) | 1.4541 (321) |
|---|---|---|---|
| C (Carbon) | ≤ 0.08 | ≤ 0.08 | ≤ 0.08 |
| Si (Silicon) | ≤ 1.00 | ≤ 1.00 | ≤ 1.00 |
| Mn (Manganese) | ≤ 2.00 | ≤ 2.00 | ≤ 2.00 |
| Cr (Chromium) | 17.50 – 19.50 | 16.00 – 18.00 | 17.50 – 19.50 |
| Ni (Nickel) | 8.00 – 10.50 | 10.00 – 14.00 | 9.00 – 12.00 |
| Mo (Molybdenum) | — | 2.00 – 3.00 | — |
| Stabilizer (Ti/Nb) | — | — | Ti ≥ 5×C |
3. Technical Specifications
| Specification Parameter | Details |
|---|---|
| Product Name | Stainless Steel Seamless Pressure Tube (Coil Form) |
| Applicable Standard | EN 10216-5:2014 (or latest revision) |
| Manufacturing Method | Seamless (Piercing / Mannesmann / Cross-Rolling) |
| Product Form | Coil Tube (盘管) — Continuous Coil Configuration |
| Outside Diameter (OD) | 6.0 mm – 426.0 mm (subject to grade and schedule) |
| Wall Thickness | 0.5 mm – 25.0 mm (per EN 10216-5 dimensional tolerances) |
| Dimensional Tolerances | EN 10216-5 / EN 10217-1 dimensional compliance |
| Surface Finish | Mill finish, pickled, or passivated (custom upon request) |
| Heat Treatment Condition | Solution Annealed (Solution Treated) |
| Test Category | TC1 (Category 1) / TC2 (Category 2) — per PED classification |
| End Condition | Plain end, beveled end, or thread-rolled (upon request) |
| Coil Packaging | Wooden pallet with protective wrapping; custom packaging available |
| Maximum Coil Weight | Up to 5,000 kg per coil (standard); custom upon request |
3.1 Dimensional Tolerance Details (per EN 10216-5)
| Parameter | Tolerance |
|---|---|
| Outside Diameter (OD ≤ 60 mm) | ± 0.10 mm to ± 0.15 mm |
| Outside Diameter (60 mm < OD ≤ 100 mm) | ± 0.20 mm to ± 0.25 mm |
| Outside Diameter (OD > 100 mm) | ± 0.5% of nominal OD (max ± 1.0 mm) |
| Wall Thickness (t ≤ 6 mm) | −10% to +15% |
| Wall Thickness (6 mm < t ≤ 10 mm) | −12% to +15% |
| Wall Thickness (t > 10 mm) | −15% to +15% |
| Length Variation (per coil) | ± 0.5% of total coil length |
| Roundness / Ovality | ≤ 0.5% of nominal OD |
4. Manufacturing Process
The production of EN 10216-5 compliant stainless steel seamless pressure tubes follows a rigorous multi-stage manufacturing process designed to ensure metallurgical homogeneity, dimensional precision, and mechanical reliability:
- Raw Material Preparation: High-purity stainless steel billets are procured from certified suppliers with full traceability. Incoming material undergoes spectrographic analysis (OES) to verify chemical composition compliance with EN 10216-5 requirements.
- Homogenization Annealing: Billets are heated to controlled temperatures (typically 1,100°C – 1,250°C) and held for extended periods to achieve uniform microstructure and eliminate segregation from the casting process.
- Hot Piercing (Seamless Forming): The homogenized billet is pierced using the Mannesmann method or cross-rolling technique to produce a seamless hollow tube blank. This process ensures a weld-free cross-section with continuous grain flow around the circumference.
- Hot Elongation / Rolling: The pierced tube is further elongated and reduced in wall thickness through multi-stand rolling mills to achieve the target outer diameter and wall thickness specifications.
- Intermediate Annealing: Periodic annealing operations restore ductility and refine grain structure between hot working stages to prevent cracking and maintain dimensional accuracy.
- Cold Drawing / Cold Rolling (if applicable): For tighter tolerance requirements, cold working operations are performed to achieve enhanced surface finish and precise dimensional tolerances.
- Final Solution Annealing: The tube is solution treated at 1,050°C – 1,150°C followed by rapid water quenching to dissolve carbides in solution, producing a fully austenitic microstructure with maximum corrosion resistance and ductility.
- Pickling and Passivation: Surface scale is removed through acid pickling (HNO₃ + HF mixture), followed by passivation treatment to restore the protective chromium oxide film on the surface.
- Coiling: The finished tube is wound into coil form using precision coiling equipment that maintains consistent coil diameter and prevents surface damage or deformation during winding.
- Quality Inspection and Testing: Comprehensive non-destructive testing (NDT) and destructive testing are performed as detailed in Section 6 below.
5. Applications
EN 10216-5 stainless steel seamless pressure coil tubes find extensive application across industries where pressure containment, corrosion resistance, and mechanical reliability are critical:
- Petrochemical and Oil & Gas: Pressure piping systems, refinery process lines, upstream wellhead equipment, and subsea pipeline connections requiring resistance to hydrocarbon corrosion and elevated temperatures.
- Power Generation: Boiler tubes, superheater and reheater elements, steam piping, and heat exchanger tubes in both fossil-fuel and nuclear power plants.
- Food and Beverage Processing: Hygienic process piping, CIP (Clean-in-Place) systems, dairy processing lines, and beverage transfer systems requiring sanitary-grade stainless steel.
- Pharmaceutical Manufacturing: Sterile process piping, bioreactor connections, and pharmaceutical fluid transfer systems requiring high-purity stainless steel with smooth internal surfaces.
- Chemical Processing: Acid and alkali handling systems, chemical reactor piping, and evaporator tubes requiring resistance to aggressive chemical media.
- Marine and Offshore: Ballast systems, fire suppression piping, and structural pressure vessels in marine environments requiring chloride resistance.
- Automotive and Aerospace: Hydraulic lines, fuel systems, exhaust components, and high-performance pressure vessels.
- Heat Exchanger Manufacturing: Coil tube form enables efficient production of hairpin tubes, gasketed tubes, and compact heat exchanger elements for HVAC and industrial thermal management systems.
6. Quality Certifications & Testing
6.1 PED Compliance (Pressure Equipment Directive)
This product is manufactured under full compliance with the European Pressure Equipment Directive 2014/68/EU (PED). The PED establishes a harmonized framework for the design, manufacture, and conformity assessment of pressure equipment and assemblies within the European Economic Area. Products bearing the CE marking under PED compliance are recognized across all EU member states and EEA countries.
6.2 Test Category Classification (TC1 / TC2)
EN 10216-5 defines two test categories that determine the level of inspection and testing applied to each tube:
| Test Category | Description | Applicable Testing |
|---|---|---|
| TC1 — Category 1 | Standard test category for general pressure applications. Provides baseline assurance of material quality and dimensional conformity. | Hydrostatic test (each tube), ultrasonic testing (UT), visual inspection, dimensional verification, chemical analysis (per heat) |
| TC2 — Category 2 | Enhanced test category for critical and safety-related pressure applications. Provides additional assurance through more rigorous non-destructive examination and material verification. | All TC1 tests PLUS: Full-length ultrasonic testing (UT), eddy current testing (ET), radiographic testing (RT) where specified, impact testing (Charpy V-notch) at service temperature, additional chemical analysis per tube, metallographic examination |
6.3 Inspection & Testing Summary
- Hydrostatic Pressure Test: Each tube is subjected to a hydrostatic test at a pressure calculated per EN 10216-5 formula: P = 2 × σ × t / D